The main goal of the proposed research is to isolate, culture and characterize mucus-producing cells and basal cells from cat and guinea pig trachea. These cells will be dissociated from trachea using non-enzymatic and enzymatic procedures. Cell viability will be determined and the cells will then be separated into enriched populations of mucus-producing and basal cells. These cell types will be placed in primary, organotypic, circumfusion and explant culture and characterized by histological, histochemical, biochemical and electron microscopic methods to determine that they are normal, non-transformed cells derived from goblet cells, submucosal glandular elements or basal cells. We will also determine the appropriate culture conditions (medium, serum, hormone and growth factor combinations, and culture substrate) that permit prolonged maintenance of these cells in a differentiated state. The cultures will then be used to determine factors (cell interactions, hormones and other agents) regulating cell differentiation and mucin production. Studies are also planned to examine the synthesis, storage and secretion of mucin after treatment of mucus-producing cells with hormones or irritants known to influence mucin production.